Here are a couple. Well, one uses integrated graphics and the other one has an AGP port:
BIOSTAR GEFORCE 6100-M9 Socket 939 NVIDIA GeForce 6100 Micro ATX AMD Motherboard - Retail
MSI K8T NEO2-F V2.0 K8T800 Pro Socket 939 1000MHz DDR400 Motherboard Retail ***Free Shipping***
800/1000FSB, ATA/133, AGP 8X, 2DDR DIMM, 4PCI, USB 2.0, Audio, Gigabit LAN, RAID/SATA
But the motherboard looks to be an ATX form factor. It's rare you'll find one in mATX these days.